JP5523309B2 - adhesive - Google Patents

Description

  The present invention provides an adhesive comprising silica produced by a silanized and structurally modified pyrolysis process. The present invention further provides for use in adhesives made of silica produced by a structurally modified pyrolysis method.

  An adhesive is defined as a non-metallic material that can bond an adherend by surface adhesion and internal strength. A number of different adhesives are known in the prior art and the majority of the adhesives used have a composition based on organic compounds. In essence, a distinction is made between adhesives that harden physically and those that harden chemically. The adhesive that is physically solidified uses the final adhesive substance (often a polymer) as it is, and solidifies the adhesive by a physical process.

  Thus, known are, for example, hot melt adhesives, dispersion-based adhesives, wet adhesives containing organic solvents, and contact adhesives. A common feature of all these types of adhesives is that the adhesive is first applied in a workable form and then solidified, for example as a result of solvent evaporation or cooling.

  In the case of chemically curing adhesives, the individual components are applied and subsequently a new product is formed by the chemical reaction of those individual components resulting in solidification. Among reactive adhesives, a two-component system and a one-component system are distinguished. In the case of a two-component system, the adhesive is applied from separate constituents and solidified by a chemical reaction. In the case of a one-component adhesive, the adhesive cures by a chemical reaction caused by changes in ambient conditions, such as increased temperature, air intrusion, evaporation, water vapor, or atmospheric oxygen.

  Chemically cured adhesive groups include, for example, cyanoacrylate adhesives, methyl methacrylate adhesives, anaerobic curable adhesives, radiation curable adhesives, phenol-formaldehyde resin adhesives, silicon, silane cross-linked polymer adhesives Agents, polyimide adhesives, epoxy resin adhesives, and polyurethane adhesives. An overview of the various adhesives is given on page 227 et seq. Of Ullmann's Enzyklopaedier der Chemie, 4th edition, volume 14 (1997).

  The use of various additives in adhesives is also known, but among them, for example, pyrogenic (fumed) silica, which is an effective thixotropic agent, is used in adhesives based on epoxy resins. (Degussa Pigment Catalog Series (2001) No. 27 and 54).

  Silicas produced by pyrolysis with a silanized surface are known from the prior art. EP 0 672 731 Al describes silanized silica. The silica described therein is not structurally modified.

  A disadvantage associated with the use of such silicas is that they can only be used at low concentrations. This is because if the adhesive is not used at a low concentration, the adhesive becomes thick and processability cannot be ensured. This means that only a small amount of pyrogenic silica can be used for the adhesive, and therefore the desired thixotropic effect cannot be ensured sufficiently.

  This disadvantage is due to the high filler content in the adhesive to improve the adhesive's fracture toughness, impact strength, scratch and abrasion resistance, shrinkage properties, thermal expansion, and thermal stability. This is especially noticeable when you want a level. In such cases, the adhesive becomes too thick and can no longer be processed, so only an insufficient amount of pyrogenic silica can be added.

  Therefore, the technical problem addressed by the present invention is to incorporate a fairly large amount of pyrogenic silica for the purpose of improving rheological properties without causing adhesive thickening and leaving the adhesive processable. It is to provide an adhesive that can be used.

The technical problem is that, according to the present invention, a silane containing a vinyl group or vinylsilyl group attached to its surface and also having a hydrophobic group such as trimethylsilyl and / or dimethylsilyl and / or monomethylsilyl attached to the surface. This is solved by using an adhesive containing silica produced by a pyrolysis method that has been modified and structurally modified. These can have the following physicochemical properties:
BET surface area m ² / g: 25-400
Average primary particle size nm: 5-50
pH: 3-10
Carbon content%: 0.1-10
Number of DBPs%: <200 or cannot be determined.

  Silanized silica is known from the prior art DE 102 39 424 A1, in which silanized silica is used in coating materials in order to improve the scratch resistance of the coating surface. EP 0 672 731 A1 likewise discloses silanized pyrogenic silicas, but these silicas are not structurally modified and they are used as thickeners for coating materials and resins.

  Surprisingly, the silica produced by the structurally modified pyrolysis method according to the present invention does not cause any thickening of the adhesive, contrary to the prior art described in EP 0 672 731 A1, and has a strong thickening action. It has been found that it can be introduced into the adhesive in considerable amounts without it. It has been found that it is particularly the structural modification that is involved in the achievement of this action, together with certain silanized groups.

  Silica produced by pyrolysis is typically produced from silicon tetrachloride, hydrogen, and oxygen by high temperature hydrolysis. Silicas produced by thermal hydrolysis can be used in adhesives according to the present invention, and they have the physicochemical data shown in Table 1 in the hydrophilic state before silanization and structural modification. In Table 1, Aerosil 200, Aerosil 150, and Aerosil 300, which are silicas produced by pyrolysis, are preferred. Particularly suitable is silica Aerosil 300 produced by a pyrolysis method.

  A pyrogenic silica of this kind is known, for example, from DE 102 39 424 A1. Pyrolytic silica is also described in Winnacker-Küchler, Chemische Technology, volume 3 (1983), page 77 of 4th edition, and also in Ulmann's Enzykloipedie dertechi2, 198. Yes.

  Surface modification with organosilanes can be carried out by spraying water first and then surface modifiers if appropriate for silica. The water used may be acidified to pH 7-1 using an acid such as hydrochloric acid. When two or more surface modifiers are used, they may be applied together, but are applied separately, sequentially or as a mixture. The one or more surface modifiers may be a solution in a suitable solvent. When spraying is over, mixing may be continued for another 5 to 30 minutes.

  Subsequently, the mixture is heat-treated at a temperature of 20 to 400 ° C. for 0.1 to 6 hours. The heat treatment may be performed under an inert gas (for example, nitrogen).

  An alternative method of surface modification of silica can be carried out by treating the silica with a surface modifier in vapor form and then heat treating the mixture at a temperature of 50-800 ° C. for 0.1-6 hours. The heat treatment may be performed under an inert gas (for example, nitrogen).

  The temperature treatment can be performed at various temperatures in a plurality of stages.

  One or more surface modifiers can be applied using a one-fluid, two-fluid, or ultrasonic nozzle.

  Surface modification can be carried out continuously or batchwise in a heatable mixer and dryer equipped with a spray device. Suitable equipment may include, for example, a proshear mixer, plate dryer, fluidized bed dryer, or fluidized bed dryer.

  Any compound suitable for attaching vinyl or vinylsilyl groups and trimethylsilyl groups and / or dimethylsilyl groups and / or monomethylsilyl groups to the silica surface can be used as a surface modifier. In particular, a vinylsilyl group and a methylsilyl group are compounds such as 1,3-divinyl-1,1,3,3-tetramethyldisilazane or dimethylvinylsilanol, or a plurality of compounds such as vinyltriethoxysilane and hexamethyldi- It can be imparted to silica by silazane or trimethylsilanol.

  The structural modification of the silica thus produced is subsequently carried out by mechanical action. After structural modification, grinding may be carried out if appropriate. If appropriate, a heat treatment may be performed after structural modification and / or grinding.

  Structural modification can be carried out, for example, using a ball mill or using a continuously operated ball mill. The pulverization may be performed using, for example, an air jet mill, a toothed disk mill, or a pinned disk mill.

  The heat treatment may be performed batchwise, for example, in a drying oven, or may be performed continuously, for example, in a fluidized bed or fluidized bed. The heat treatment may be performed under an inert gas (for example, nitrogen).

  The adhesive preferably contains 1 to 40%, preferably 2 to 30%, more preferably 4 to 10% by mass of silica produced by a structurally modified pyrolysis method.

  In a preferred embodiment, the adhesive comprises as its base polymer an epoxy resin, an unsaturated polyester resin, a polyurethane, a silane-terminated polymer, a vinyl ester resin, an acrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl ether, ethylene-vinyl acetate. , Ethylene-acrylic acid copolymer, polyvinyl acetate, polystyrene, polyvinyl chloride, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, polysulfide, polyethylene, polypropylene, fluorinated carbohydrate, polyamide, saturated polyester and copolyester, Phenol-formaldehyde resin, cresol / resorcinol-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin, polyimide, poly Including lens imidazole, polysulfone, or a compound selected from the group consisting of mixtures thereof.

  In a preferred embodiment, the structurally modified pyrogenic silica may be introduced into the epoxy resin and then mixed with the adhesive together with the resin.

  Adhesives moisten the surface by the respective chemical composition and the physical state that prevails when applied to the adherend, and the adhesive layer required to transfer force between the adherends at the bonded joint Is a product that forms. Similar to the sealant, the adhesive is in addition to the base polymer, and similar components such as solvents (eg, ketones), water, fillers (eg, chalk), thixotropic agents (eg, pyrogenic silica), adhesion promoting Agents (eg, silanes), color pastes (eg, pigment grade carbon black), as well as additional additives (eg, catalysts, degradation inhibitors), and the like.

  Compared to the sealant, the adhesive has a higher tensile shear strength and a lower elongation value. That is, the adhesive is hard to elastic, and the sealant is elastic to plastic.

  Epoxy resin is preferably used as the base polymer of the adhesive. The epoxy resin is produced, for example, by condensing 2,2-bis (4-hydroxyphenyl) propane and epichlorohydrin in a basic medium. Depending on the equivalents of both reactants used, the product is a glycidyl ether having a different molar mass. In recent years, epoxy resins based on bisphenol F, novolac epoxy resins, and alicyclic and heterocyclic epoxy resins have also become important.

  Epoxy resins are insufficient film-forming elements by themselves, and thus molecular expansion using an appropriate crosslinking agent is required. Examples of cross-linking agents used for epoxy resins include polyamines, polyaminoamides, carboxylic anhydrides, and dicyandiamide. Among amine curing agents, a distinction is made between aliphatic, cycloaliphatic, aromatic and araliphatic polyamines. Curing is performed without removal of the reaction product. This generally requires the addition of a reactive hydrogen atom to the epoxide group and involves the formation of a hydroxyl group.

  An unsaturated polyester resin is preferably used as the base polymer of the adhesive. These are obtained by polycondensation of unsaturated and saturated dicarboxylic acids or polycarboxylic acids with alcohols. Given the appropriate reaction form, the double bond is kept in acid and / or alcohol, allowing a polymerization reaction with an unsaturated monomer such as styrene. Unsaturated dicarboxylic acids preferably used are maleic anhydride, maleic acid and fumaric acid.

  Preferably used saturated dicarboxylic acids are ortho-phthalic acid and ortho-phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid, azelaic acid, sebacic acid, hexachloroendomethylenetetrahydrophthalic acid Tetrabromophthalic acid.

  Preferably used glycols are propylene 1,2-glycol, ethylene glycol, butylene glycol, neopentyl glycol, 2,2,4-trimethylpentane-1,3-diol, dibromoneopentyl glycol, diethylene glycol, triethylene glycol, Dipropylene glycol, pentaerythritol diallyl ether, and dicyclopentadiene.

  Preferred crosslinking monomers are styrene, α-methyl styrene, meta- and para-methyl styrene, methyl methacrylate, diallyl phthalate, triallyl cyanurate.

  This list does not list all possible starting materials. One skilled in the art can use other compounds depending on the status of the raw materials. Furthermore, the addition of dicyclopentadiene is customary, and as a result, the reactivity of the resin is altered. The “unsaturated polyester resin” produced can be used as it is or as a dilution using a reactive monomer. Reactive monomers are styrene, stilbene, esters of acrylic acid, esters of methacrylic acid, diallyl phthalate, and other unsaturated compounds, but these are adequately mixed with sufficiently low viscosity and unsaturated polyester resins. It shall have

  A polyurethane resin is preferably used as the base polymer of the adhesive. The polyurethane is obtained from isocyanic acid. As a very reactive compound, it is very easily added to compounds with active hydrogen atoms. In this reaction process, the double bond between nitrogen and carbon is broken, active hydrogen is attached to nitrogen, and oxygen-bonded radical is attached to carbon to form a urethane group. In order to obtain the higher molecular weight of this kind of cross-linked polyurethane required for the adhesive layer and sealant layer, a reaction partner such as a diisocyanate or triisocyanate, for example a diphenylmethane having a polymer part, which is a starting product having at least two functional groups Provided is the reaction product of 4,4-diisocyanate (MDI) or tolylene diisocyanate (TDI) and a polyol, and a polyhydric alcohol (diol or polyol, compound having two or more hydroxyl functionalities in the molecule). There is a need. This type of alcohol may be present, for example, in the form of a saturated polyester, which is produced using an excess of polyhydric alcohol.

  Two-component reactive adhesives are composed of a low molecular weight polyisocyanate and a relatively low molecular weight polyester polyol, such as a polyalkylene adipate. After mixing of the two components, urethane groups are formed in the adhesive or in the adhesive layer.

  One-component reactive adhesives are composed of relatively high molecular weight polyurethane, which solidifies by reacting with water vapor in the atmosphere. In principle, this situation is also one of two interacting chemical components, but only one physical component is supplied to the adhesive processing. When reacting with water vapor, simple low molecular weight polyisocyanates form relatively hard and brittle adhesive layers with low strength values, so the one-component system starts with a precrosslinked polymer known as a prepolymer . Such compounds are made from a relatively high molecular weight polyol and a stoichiometric excess of isocyanate. Thus, the existing compound already has a urethane bond, but also has a reactive isocyanate group that easily reacts with water vapor. Reaction with water initiates the formation of urea bonds. The primary amine formed in the course of the decomposition reaction reacts immediately with further isocyanate groups to form polyurea. Thus, in the case of a one-component system, a fully cured polymer contains not only a urethane compound but also a urea compound.

  Solvent type polyurethane adhesives can be used as a physical solidification system and as a chemical reaction system. In the case of a physical solidification system, the polymer takes the form of a high molecular weight hydroxyl polyurethane and the solvent used is, for example, methyl ethyl ketone. The chemical reaction system further includes hydroxyl polyurethane and additional polyisocyanate as a crosslinker and as a second component.

  Dispersion-based adhesives include high molecular weight polyurethanes as dispersions in water.

  In the case of thermally activatable polyurethane adhesives, the isocyanate component is “capped” or “blocked” in the compound, and the isocyanate component is removed only at relatively high temperatures.

  Reactive polyurethane hot melt adhesives are made using relatively high molecular weight crystalline and soluble diol and isocyanate components. These components are applied to the adherend as a hot melt adhesive at approximately 70 ° C. to 120 ° C. After cooling, the bond provides sufficient initial strength, which allows for rapid further processing. Subsequently, further exposure of the reactive isocyanate groups still present to the water vapor results in cross-linking by urea linkages to form an adhesive layer polymer.

  Silane-terminated polymers are preferably used as the base polymer for the adhesive.

  The term “silane-terminated polymer” or “silane-modified polymer” carries a silyl group having at least one hydrolyzable bond, either at the chain end or side chain, but the polymer backbone is typical of siloxanes. All prepolymers that do not contain typical siloxane bonds.

  In general, it is believed that any silane modified polymer will have hybrid properties regardless of its chemical structure. Curing is similar to that of silicon and other properties are formed by various possible polymer backbones between silyl groups. Silane-terminated or silane-modified polymers can be classified between polyurethane and silicon with respect to their structure.

  The synthesis of silane-modified polymers involves multiple stages. The initial main component is polyoxypropylene glycol containing 2 or 3 hydroxyl groups, which are converted into the corresponding bisallyl compounds. The compound is reacted to form the desired end product, bis (3- (methyldimethoxysilyl) propyl) polyoxypropylene.

  The resulting silyl groups introduced into the chain crosslink with each other by a mechanism as known in silicon chemistry, i.e. with the removal of small amounts of water or methanol, thereby producing an elastic and insoluble network.

There are further possible ways to obtain sealants and adhesives based on silicon-modified polymers, for example, reaction of NCO-terminated prepolymers with correspondingly reactive aminosilanes or mercaptosilanes. The polymer backbone may contain all possible rational structural elements such as ether, ester, thioether, or disulfide bridges. Similarly, NH ₂ -, SH-, or also conceivable reverse example of OH- terminated prepolymer can be reacted with an isocyanate silane. Adding a terminal mercapto group to a C—C double bond in a prepolymer or silane provides a further technically interesting route.

  Vinyl ester resin is preferably used as the base polymer of the adhesive. In the chemical aspect, vinyl ester resins have a particular relationship with UP resins, particularly as far as curing reactions, processing techniques, and fields of use are concerned. These resins are polyadducts of liquid epoxy resins and acrylic acid. As a result of the reduction of ester groups in the molecular chain, these resins have better hydrolysis resistance in parallel with effective elasticity and impact toughness. The monomer used for crosslinking is the same as that for the unsaturated polyester resin, in particular styrene.

  Acrylate is preferably used as the base polymer of the adhesive. The collective term “acrylate-based adhesives” encompasses all reactive adhesives in which curing occurs through acrylic-carbon double bonds.

Of particular importance for methacrylate esters and α-cyanoacrylates in adhesive formulations. Curing of the acrylate adhesive is accomplished by addition polymerization, but in the process, the initiator causes a chain reaction that leads to continued curing of the adhesive. Polymerization of “acrylate” adhesives can be initiated by free radicals or, in the case of α-cyanoacrylates, by anions. Depending on the polymerization mechanism utilized for curing, the acrylate adhesives are in the following groups:
Anionic curable adhesive: α-cyanoacrylate one-component adhesive, free radical curable adhesive: anaerobic one-component adhesive, free radical curable adhesive: two-component adhesive.

  In the case of sealants based on polyacrylates or acrylate copolymers and polymethacrylates, a distinction is made between solvent-containing systems and aqueous systems. Polyacrylate sealants are physically cured by evaporation of the solvent or dispersion water.

  Polyvinyl acetate is preferably used as the base polymer of the adhesive. Polyvinyl acetate is a polymerization product of vinyl acetate. Due to the strong polar acetate groups present in the molecule, polyvinyl acetate has very good adhesion to many adherend surfaces. Use is primarily as a dispersion-based adhesive having a solids content of approximately 50% to 60%, and optionally based on a vinyl acetate copolymer (eg, with vinyl chloride).

  Polyvinyl alcohol is preferably used as the base polymer of the adhesive.

  Polyvinyl alcohol occurs as a hydrolysis product of polyvinyl acetate and other similar polyesters. Depending on the molecular weight, polyvinyl alcohol takes the form of a liquid with a somewhat higher viscosity. This is used, for example, for bonding cellulosic materials such as paper, cardboard, wood, etc. and as protective colloids for stabilizing and increasing the solidification rate of dispersion-based adhesives.

  Polyvinyl ether is preferably used as the base polymer of the adhesive. Of the polyvinyl ethers, three polymers, polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, are of particular interest as adhesive bases.

  Polyvinyl ether with a medium degree of polymerization is a tacky plasticized resin with very good adhesion to porous and smooth surfaces. Polyvinyl methyl ether can in particular be re-wetted due to its water solubility and can therefore be used as a sticky on label paper, for example as a mixture with dextrin or glue, improving their adhesion It is worth noting. Due to its permanent tackiness, polyvinyl ether is also used for pressure sensitive adhesives.

  Ethylene-vinyl acetate, which is a copolymer of ethylene and vinyl acetate, is preferably used as the base polymer of the adhesive. In its molecular structure, vinyl acetate molecules are randomly incorporated into the ethylene chain. While removal of acetic acid renders polyvinyl acetate relatively unstable under temperature loading, copolymers with ethylene are significantly more resistant to oxidation and thermal degradation. For this reason, EVA copolymers with a proportion of approximately 40% vinyl acetate are included in an important group of hot melt adhesive bases.

  An ethylene-acrylic acid copolymer is preferably used as the base polymer of the adhesive. These are copolymers of ethylene with acrylic acid and / or acrylic esters.

  These copolymers, which combine the chemical resistance of polyethylene with the good properties of acid and / or ester moieties, represent an important base polymer for hot melt adhesives. The ester component used is preferably ethyl acrylate.

  Polyvinyl acetal is preferably used as the base polymer of the adhesive. Polyvinyl acetals are produced by the action of aldehydes on alcohols. The most important acetals for adhesive production are polyvinyl formal and polyvinyl butyral. Both serve as the plasticizing component of the phenolic resin-based adhesive. Furthermore, polyvinyl butyral is used as an adhesive film in laminated safety glass.

  Polystyrene is preferably used as the base polymer for the adhesive. This monomer is mainly used in two fields as a component of the adhesive base, one as a comonomer with a plasticizing monomer, in particular butanediene, in the production of styrene-butadiene dispersions. One is used as a “polymerizable” solvent for copolymerization with unsaturated polyesters.

  Polyvinyl chloride is preferably used as the base polymer for the adhesive. This is to provide vinyl chloride / vinyl acetate copolymers in solvent-based adhesives, dispersion-based adhesives, heat seal adhesives, more specifically for plastisol adhesives and as copolymers with vinyl acetate. In addition, it is also used as an auxiliary for high frequency welding.

  Styrene-butadiene rubber is preferably used as the base polymer of the adhesive. Styrene-butadiene rubber is a typical example of a thermoplastic elastomer that combines the applicability of an elastomer with the applicability of a thermoplastic material. Styrene-butadiene copolymer (SBS) and styrene-isoprene copolymer (SIS) are so-called triblock copolymers, which are linearly constructed by identical monomer units that are continuous in individual blocks. The end block is a polystyrene segment, while the intermediate block is polybutadiene (styrene-butadiene-styrene block copolymer, SBS) or isoprene (styrene-isoprene-styrene block polymer, SIS).

  The ratio of styrene to butadiene or styrene to isopropylene is approximately 1: 3. Unlike adhesive layer polymers whose elastic properties are due to the addition of a plasticizer, this method provides “internal plasticization”. A special advantage of these rubber copolymers is the ability to form an adhesive layer with good adhesion and high flexibility. Therefore, there is an important application when the adherend to be bonded is subjected to high deformation stress in practical use, for example, in footwear or when having a rubber / rubber bond or rubber / metal bond.

  Chloroprene rubber (CR) is preferably used as the base polymer of the adhesive. Chloroprene rubber (polychloroprene) is produced as a polymerization product and copolymerization product of chloroprene (2-chlorobutadiene). In addition to good adhesion, linear polymers have a strong tendency to crystallize, which contributes to the relatively high strength on the adhesive layer side. These polymers and copolymers are important bases for contact adhesives. The double bonds present in the polychloroprene molecule allow further cross-linking with correspondingly reactive molecules. Thermal solidifying components used for this purpose include isocyanates and phenolic resins.

  Nitrile rubber (NBR) is preferably used as the base polymer of the adhesive. Nitrile rubber is a copolymer of butanediene and approximately 20% to 40% acrylonitrile. This high proportion of acrylonitrile imparts effective plasticizer resistance to these polymers, thereby making them very suitable for bonding plasticized plastics, for example.

  Butyl rubber is preferably used as the base polymer of the adhesive. Butyl rubber is a copolymer with isoprene composed mostly of isobutylene. Within this linear molecule there are very high proportions of chains characterized by saturation in the form of long polyisobutylene segments, where no further crosslinking is possible. The only crosslinkable component is the isoprene molecule, so the overall properties of butyl rubber are determined by the proportion of the number of double bonds defined by isoprene. The reactivity can be further influenced by incorporating monomers containing chlorine or bromine.

  Polysulfides are preferably used as the base polymer for the adhesive. The raw material for polysulfide sealants has long been known under the trade name of Thiokol®. Polysulfide polymers are obtained by reacting dichloroethyl formal with sodium polysulfide. The molecular weight of the liquid polymer is 3000 to 4000. These can be converted to a final rubber elastic state by reaction with an oxidizing agent such as manganese dioxide.

  Polyethylene is preferably used as the base polymer of the adhesive. Low molecular weight types with a melt index ranging from 2 to 2000 g / 10 min are used as hot melt adhesives in the paper and cardboard industry in combination with tackifying resins and microwaxes.

  Polypropylene is preferably used as the base polymer for the adhesive. Polypropylene is used as a base for hot melt adhesives with moderate strength properties, more specifically in the form of atactic polypropylene.

  Fluorinated carbohydrates are preferably used as the base polymer for the adhesive. Polyfluoro-ethylene-propylene is a copolymer of tetrafluoroethylene and hexafluoropropylene and has been studied as a base for hot melt adhesives. The advantage of these products is high long-term temperature durability.

  Polyamide is preferably used as the base polymer of the adhesive. Polyamides represent some of the most important bases of hot-melt adhesives that physically harden. Suitable for the production of polyamides are the reactions described below, which are typically carried out in the molten state under a nitrogen atmosphere: polycondensation of diamines with dicarboxylic acids; polycondensation of aminocarboxylic acids; Polycondensation from lactam; polycondensation of diamine with dimerized fatty acid.

  Saturated polyesters and copolyesters are preferably used as the base polymer for the adhesive. Saturated polyesters and copolyesters are produced by polycondensation from dicarboxylic acids and diols. These are important bases for hot melt adhesives.

  Phenol-formaldehyde resin is preferably used as the base polymer of the adhesive. These polymers arise from the polycondensation reaction of phenol and formaldehyde and form highly crosslinked phenolic resins that are used, for example, as adhesive bases for aircraft manufacturing. Pure phenol-formaldehyde resins are generally too brittle. For this reason, they are modified with thermoplastic polymers, which are carried out for example by copolymerization or cocondensation with polyvinyl formal, polyvinyl butyral, polyamide, epoxy resins or elastomers such as polychloroprene and nitrile rubber. .

  Cresol / resorcinol-formaldehyde resins are preferably used as the base polymer of the adhesive. In addition to phenol as the starting monomer for formaldehyde condensation, phenol derivatives such as cresol and resorcinol are also used as co-reactants.

  Urea-formaldehyde resin is preferably used as the base polymer of the adhesive. A number of nitrogen-containing organic compounds can be polycondensed with aldehydes. For application as adhesives, urea and melamine are particularly important. For urea-formaldehyde resins, the series of reactions is first performed in the form of an addition reaction in a weakly acidic solution. The actual polycondensation reaction leading to the formation of the polymer adhesion layer results in a highly crosslinked polymer by the formation of either ether or methylene bridges.

  Melamine-formaldehyde resin is preferably used as the base polymer of the adhesive. Like urea, melamine reacts with formaldehyde to form a methylol compound. As in the case of the urea reaction, polycondensation with these compounds proceeds by methylene or methylene ether linkage, forming a high molecular weight, highly cross-linked, hard and sometimes brittle adhesive layer.

  Polyimide is preferably used as the base polymer of the adhesive. Experiments on the use of polyimide were conducted with an interest in obtaining organic-based adhesives that could be used at high temperature loads. The production of technically usable polyimides is carried out by the reaction of tetrabasic acid anhydrides such as pyromellitic acid anhydride with aromatic diamines such as diaminodiphenyl oxide. Use as an adhesive is achieved in the form of a solution or film starting from a precondensate.

  Polybenzimidazole is preferably used as the base polymer of the adhesive.

  Polybenzimidazoles should likewise be classified as adhesives with high heat resistance. These are produced by a polycondensation reaction between an aromatic tetramine and a carboxylic acid.

  Polysulfone is preferably used as the base polymer of the adhesive. Polysulfones likewise belong to the group of heat-resistant adhesives. These are obtained, for example, by a polycondensation reaction of dihydroxydiphenyl sulfone and bisphenol A.

  The adhesive of the present invention is preferably used for casting compounds, but these are used as coating agents in the electrical and electronic industries.

  It is surprising that the described silica can be incorporated into the adhesives of the invention relatively quickly and, despite the high levels of fillers, no disadvantages have been observed with regard to the viscosity and processability of the adhesive. It was to be done.

  The present invention is silanized and structurally modified containing a vinyl or vinylsilyl group attached to its surface and also having hydrophobic groups such as trimethylsilyl and / or dimethylsilyl and / or monomethylsilyl attached to the surface Further provided is the use of silica produced by pyrolysis in adhesives.

  The following examples are intended to clarify the invention in more detail.

Example Example 1
Production of Silanized and Structurally Modified Silica Production is carried out using silica produced by pyrolysis or silica from Table 1. The surface modifier used is, for example, vinyltriethoxysilane and hexamethyldisilazane in the case of silica 4 in Table 2. Further details of the surface modifier used are given in Table 2. The silica is charged into a mixer and sprayed first with water and then with organosilane while stirring vigorously. When spraying is completed, mixing is further continued for 15 to 30 minutes, and then heat treatment is performed at 100 to 160 ° C. for 1 to 3 hours. The heat treatment may be performed under an inert gas (for example, nitrogen).

  Structural modification of the silanized silica is carried out by mechanical action in a continuously operated ball mill and possibly subsequent grinding. Heat treatment may be performed after the pulverization. The pulverization is performed using an air jet mill, a toothed disk mill, or a pinned disk mill. The heat treatment may be performed batchwise in a drying oven, or continuously in a fluidized bed or fluidized bed dryer. Table 2 below shows the reaction conditions for the individual silicas used from Table 1.

Preparation of comparative silica Charge 2 kg of AEROSIL® into a mixer and stir vigorously, first 0.1 kg of water, then 0.4 kg of hexamethyldisilazane and 0.17 kg of vinyltriethoxy. Spray the mixture with silane. When spraying is complete, mixing is continued for an additional 15 minutes and the reaction mixture is first heat treated at 50 ° C. for 5 hours and then at 140 ° C. for 1 hour.

  The physicochemical characteristics of the resulting silanized silica are shown in Table 3 below.

Example 2
Rheological properties In Example 2, the rheological properties of the structurally modified pyrogenic silica used are determined in the epoxy resin Renlam M1 (Huntsman). The respective viscosities with the comparative product and the structurally modified silica used in the present invention are elucidated. Viscosity is measured before and after silica addition.

  The determination of rheological properties is carried out by the method described below.

  167.5 g of Renlam M-1 and 10 g of silica are weighed into a 350 ml beaker and the dissolver disc is completely submerged. The lid is then closed and the silica is homogenized at a speed n1 of 1000 rpm until completely mixed. As soon as the silica is thoroughly mixed, the speed is increased to n2 = 3000 rpm and dispersion is carried out under vacuum for 3 minutes. Viscosity is determined using a Brookfield DV III rheometer. The reported viscosity values were obtained at room temperature of 25 ° C. The measurement is No. Perform at 2.5 rpm using 7 spindles.

  Table 4 below shows the results.

  From Table 4 it is clear that the viscosity of the comparative silica increases very significantly when added to the epoxy resin. In comparison, the addition of silica S4 results in a significantly lower viscosity of the epoxy resin. This experiment shows that even at high levels of filler, the rheological properties of the epoxy resin are not adversely affected and thickening does not occur, as would be expected by one skilled in the art from the prior art.

Example 3
Properties for incorporation into polyester adhesive resin 100 g of Palatal A 410 (polyester resin, Bufa) is weighed into a 350 ml beaker and adjusted to 25 ° C. in a water bath. Insert the beaker into the aluminum insert of the dissolver mounting device. The stirrer is submerged to the desired depth t = 10 mm (upward from the bottom of the beaker) and operated at a speed n of 500 min− ¹ . Place 3 g of silica uniformly on the resin surface and start the stopwatch. The time required for the silica to be homogenized in the resin is measured.

  Table 5 shows the results.

  The silica S4 of the present invention can be incorporated into Palatal A 410 very quickly within 58 seconds. In contrast, the comparative example requires 196 seconds for complete mixing. Thus, time is saved to approximately 30%.

Claims (7)

Silanized and ball or silica produced pyrogenically which is structurally modified by mechanical action of the continuous operation type ball mill viewed including, where, silica prepared by the thermal decomposition method is adhered to the surface a vinyl group or vinyl silyl group is, the deposited trimethylsilyl groups on the surface thereof, and containing a hydrophobic group selected from the group consisting of dimethylsilyl groups and monomethyl silyl group, and
Adhesive base polymer is epoxy resin, unsaturated polyester resin, polyurethane, silane-terminated polymer, vinyl ester resin, acrylate, polyvinyl acetate, polyvinyl alcohol, polyvinyl ether, ethylene-vinyl acetate, ethylene-acrylic acid copolymer, polyacetic acid Vinyl, polystyrene, polyvinyl chloride, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, polysulfide, polyethylene, polypropylene, fluorinated carbohydrate, polyamide, saturated polyester and copolyester, phenol-formaldehyde resin, cresol / resorcinol -Formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin, polyimide, polybenzimidazole, polysulfone And it is selected from the group consisting of a mixture thereof containing compounds, adhesives. The adhesive according to claim 1, wherein the silica produced by the pyrolysis method is pulverized after structural modification. The adhesive according to claim 1, wherein the silica produced by the pyrolysis method is heat-treated after structural modification and / or pulverization. Wherein the adhesive, characterized in that it contains 1 to 40 wt% of the silica prepared in the previous SL pyrogenic adhesive of claim 1. A casting compound based on epoxy resins, the mixed compound in the adhesive, characterized in that it comprises a silica prepared in the previous SL pyrogenic adhesive of claim 1.   The adhesive according to claim 1, further comprising a solvent, water, a filler, a thixotropic agent, an adhesion promoter, a color paste, a catalyst, and / or an anti-aging agent.   2. The adhesive according to claim 1, wherein the adhesive is used as a casting compound in a coating agent in the electrical or electronic industry.